2. Voluntary assumption of risk (volenti non fit injuria)
This defence applies where the plaintiff freely and knowingly agreed to accept the legal risk of harm arising from the defendant’s negligence. If established, it is a complete defence and the claim fails entirely.
The defence is strictly confined by its requirements. It is not enough that the plaintiff knew there was some risk or merely acted carelessly. The defendant must show that:
- the plaintiff consented to absolve the defendant from any legal responsibility for the
defendant’s conduct;
- the plaintiff’s consent was voluntary; and
- the plaintiff had full knowledge of the nature and extent of the risk that he had assumed.
The requirement of knowledge is judged subjectively: the particular plaintiff must actually appreciate the specific risk that materialised, not merely what a reasonable person would have appreciated.
Knowledge of a risk is not the same as consenting to absolve the defendant from legal responsibility. Mere knowledge of risk is insufficient. A plaintiff may know that an activity is dangerous without agreeing to waive all legal rights against a negligent defendant.
The law therefore distinguishes between accepting that an activity carries inherent risks and accepting the risk of injury caused by the defendant’s failure to take reasonable care. A person may be taken to accept the ordinary risks of an activity without agreeing to waive any claim arising from negligence that goes beyond those ordinary risks.
Because volenti is a complete defence, clear proof of the required consent, voluntariness, and knowledge is needed.
In one case, both the defendant pilot and the plaintiff had been drinking heavily before deciding to take a light aircraft flight. The plaintiff agreed to go, drove the defendant to the airfield, and helped prepare the aircraft. The plane crashed shortly after take-off, killing the defendant and seriously injuring the plaintiff. The court held that volenti applied: the plaintiff was not so intoxicated that he was unable to appreciate the nature and extent of the risks involved and had voluntarily accepted it by flying with the defendant whom he knew was extremely drunk.
The defence is unlikely to succeed where:
- the plaintiff had no real freedom of choice;
- the plaintiff was under social, practical or economic pressure;
- the plaintiff did not fully understand the nature or extent of the danger; or
- the plaintiff merely accepted the ordinary risks of an activity, but not negligence going beyond those risks.
For that reason, it is rarely made out in rescue cases. A person who takes a risk in order to save life or prevent serious injury is not usually treated as having voluntarily accepted the legal risk in the full sense required by the defence.
An important distinction is between:
- accepting that an activity carries some inherent risk; and
- accepting the risk of injury caused by the defendant’s failure to take reasonable care.
For example, participants in sport may be taken to accept the ordinary risks inherent in the game. But that does not mean they consent to reckless or seriously dangerous conduct outside what is properly part of the sport.
Similarly, a person who engages in a risky activity does not automatically agree to absolve others from liability for negligent conduct.
Volenti should also be distinguished from contributory negligence. Contributory negligence means the plaintiff acted without reasonable care for his or her own safety, so damages are reduced. Volenti means the plaintiff fully accepted the relevant risk, so the claim is defeated altogether. Because volenti is a complete defence, courts require clear evidence before finding that it applies.
